1. Technical Field
The presently disclosed subject matter relates to interior lamps, and in particular, to an interior lamp configured for use in a vehicle that can radiate light with different color tones and light qualities.
2. Related Art
Conventional interior lamps have been proposed, which include the following structures. One of such structures is configured to include a cover lens and two types of light sources which are a white illumination lamp and a colored illumination lamp. In this structure, the white illumination lamp is arranged closer to the cover lens than the colored illumination lamp (for example, see Japanese Patent Application Laid-Open No. Hei 10-194041). According to this structure, white light emitted from the white illumination lamp is radiated through the cover lens into a vehicle compartment without coloring the white light by the colored illumination lamp. In this instance, the white light from the white illumination lamp is used to, for example, serve as an overhead reading lamp while the colored light from the colored illumination lamp is used to serve as a foot light when a vehicle door is opened or closed.
Another example of a conventional device includes a structure that is configured to include a plurality of white LEDs arranged in a line, a light guide plate, and LEDs capable of emitting three primary colors (red, green and blue) which are arranged on both sides of the light guide plate (see, for example, Japanese Patent Application Laid-Open No. 2003-127769). White light is emitted from the white LEDs. Red light, green light, and blue light are emitted from the three primary color LEDs, respectively, and are guided through the light guide plate. Then, the white light and R, G, and B light are combined and adjusted to be mixed into a desired mixed light (including pseudo white light) and reflected by a reflector to be directed to a lens. The reflected light (indirect light) is radiated through the lens into a vehicle compartment.
In this instance, the white light from the white LEDs is used so that the vehicle compartment is brightly illuminated therewith. The colored light or pseudo white light from three primary color LEDs can be used for illuminating the vehicle compartment with light that is relatively not so bright, or for imparting an illumination effect of one's taste.
The interior lamp disclosed in Japanese Patent Application Laid-Open No. Hei 10-194041 can illuminate a vehicle compartment with light which is formed by white light and colored light through the same cover lens. Accordingly, even when the light tone is switched from white to a certain color other than white and vice versa, the light quality is not changed. With this illumination light, certain illumination effects (providing comfortable environment, etc.) cannot be achieved sufficiently, resulting in lack of merchandizability.
The interior lamp disclosed in Japanese Patent Application Laid-Open No. 2003-127769 can illuminate the vehicle compartment with white light from the white LEDs, primary color light from each of the three primary colored LEDs, or mixed light (including pseudo white light) of R, G, B light through the same lens. Accordingly, as in the case disclosed in Japanese Patent Application Laid-Open No. Hei. 10-194041, the interior lamp disclosed in Japanese Patent Application Laid-Open No. 2003-127769 results in insufficient merchandizability.
Furthermore, the light with which the vehicle compartment is illuminated is an indirect light which is reflected once by the reflector. Accordingly, in this case the reflection loss may deteriorate light utilization efficiency. Namely, there is a problem in which the light intensity may be reduced.